Moesia

Moesia was a province of the Roman Empire that was located in the Balkans. The province included most of Serbia in addition to northern Macedonia and Bulgaria and the Northern Dobruja region of eastern Romania's coastline, and its capital was Abrittum (Dobrich, Serbia). As a frontier province, Moesia was prone to invasion by Scythians and Sarmatians, and it remained a province of the Byzantine Empire even after the fall of the Western Roman Empire. In the 6th century, Moesia was invaded by the Slavs, and at the end of the 7th century the Bulgars of Central Asia conquered lower Moesia. The First Bulgarian Emprie was founded in what used to be Moesia, and the Byzantines lost the region.